Geekworm for Raspberry Pi UPS, X728 (Max 5.1V 6A) UPS & Power Management Board with AC Power Loss Detection|Auto Power On|Safe Shutdown|Battery Capacity Reading|Low Battery Auto Shutdown|Buzzer

I put this UPS HAT on a Raspberry Pi 4B as part of a little “mobile lab” setup and it has been great so far. My stack is a Pi 4B on Raspberry Pi OS, a GeekPi PWM cooling hat with a small screen I am not really using yet, and a Panda PAU0F USB Wi-Fi adapter, all powered through this board with two 18650 batteries. Setup was easy. I watched the video the seller links, dropped the 18650 cells into the holder, plugged USB-C power into the hat, and let the hat feed the Pi through the GPIO header. It powered up on the first try and after that I mostly stopped thinking about it. The real test for me was what happens when you pull the plug. When I unplug the USB-C input, the Pi just keeps running. No reboot, no undervoltage icon, no SD card complaints. I have let this setup run on battery for a little over three hours and it stayed completely stable the whole time, which is more than enough for how I plan to use it. I actually started with a regular USB power bank and assumed that would work as a UPS. It did not. As soon as I unplugged the power bank from the wall, the Pi died instantly. That is what pushed me to try a proper UPS hat, and this one does exactly what I wanted. It turned my Pi 4 into something I can unplug, move around, or briefly lose mains on without worrying about corrupting the SD card.

I use these in an rpi5 cluster that is rackmounted. I choose this ups for my rpi5 because most of the dedicated rpi5 ones are bottom ones that don't work with the rack front io cutout due to increasing height below the rpi. These work well, but i wish the usb c power port was rear or forward facing as with my rpi cluster using the side is difficult cable managment wise. I've actually broke a usb c port off before taking the cluster out for maintainance. I particularly like the power switch header for safe shutdown with a momentary switch. It also has a power button on the board thats easier to access than the one on back of the pi.

This UPS meets most of my needs, but I wish the python2 scripts for managing it were updated by the manufacturer and if possible made compatible with more and newer operating systems. After rewriting some things from the .py scripts provided on the wiki it works with OpenWRT enough to poll the battery percentage and do a controlled shutdown before the battery reaches low voltage cutoff, but I left it at 'good enough' so I don't have power loss detection or 1 or 2 power button functions working yet. One odd thing I noticed about this UPS is the battery percentage fluctuates on AC power. When I put the (brand new) cells in the first time I noticed they charged to 100%, then the controller goes into some kind of discharge cycle that takes it down close to 90% before charging back to 100% and repeating... over and over. From what I have read lithium *should* be okay in this range, and hopefully daily repeated cycles won't wear out the battery in just the top 10% of charge after thousands of cycles like this. Maybe the charge controller needs a full discharge/charge cycle to learn the capacity? More research needed, but they are all brand new balanced cells. I've had a few short power outages in the past couple of months, but nothing long enough to test the full runtime on the 4 18650 cells that are connected. I expect to get a few hours out of them just running the Pi and a couple of USB NICs. There are some other UPS solutions for the Pi that can be scheduled to boot at a certain time, but for a routing device this seems to be fairly solid so far. I like the selection modular 18650 holders with mounting holes and standoffs!

I purchased one of these for my OctoPi/OctoPrint setup and I was having issues with the X728. The unit would turn on the RPi just fine, I could read the battery level just fine, and I could run the power test (too see if the RPi was being powered off batteries or the 5V input. But, I could not get the soft shutdown and power off to work at all. I actually returned the first one thinking it was defective and right after that, Geekworm contacted me, via the Amazon portal, to see if they could do anything to help me get this working. After several email exchanges of trying different things, I found, in my case, that one of the 3rd-party plug-in for OctoPrint was interfering with the communications for the soft shutdown. While they didn't come up with the exact solution, they hung in there with me with suggestions while we got it diagnosed and working.

Battery holder broke. Good idea overall though.